Natural gas formations are frequently found in combination with oil and/or water formations that are open to the production piping. If the fluid head produced by oil or water becomes too great, the flow of natural gas from the well is reduced or stopped. Accordingly, the fluid must be removed from the well in order to maintain a viable flow of natural gas.
Conventional fluid pumps for use in gas and oil wells use a rocking arm-type pump that raises and lowers a string of sucker rods to move the fluid from the well. Such pumps may be powered by electrical motors if electrical power is available at a well site or internal combustion engines may be used to run a generator for producing electrical power. In either case, there is a large energy expense associated with removing fluids from the well.
A pneumatic pump unit (Pneulift.RTM., by Maranatha Industries) has been developed to use natural gas as a lifting medium. Compressed gas is applied on both an up stroke and a down stroke to drive ram cylinders for removing liquids from natural gas wells. A complex system, including two separate pneumatic units and a stored gas supply, is provided to control the rate of the down-stroke of the unit.
In accordance with the present invention, pressurized natural gas that is available at or near a well site is used to operate a pump where the gas is returned to the distribution network on each pump cycle. Simple valve systems control the operating speed of the unit.
Various objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.